By Mike from Odenville, AL
Do a search on the name and the date. It will take some digging, but remember, it is only worth what someone will pay. The 1812 may not be the date, but the date the maker became a master maker and his design was recognized. Also if he was a well known, it could be a fake label, or a violin made in his factory.
Do your own research first as suggested by Chloelizabeth to get a general education, but when it comes to violins, you will need and expert opinion. As you local school's orchestra director who they use for repairs and vaules, or if your school doesn't have an orchestra, the band director may be able to put you in touch with someone.
The value of most violins is in their sound when they're played, not necessarily the maker. Certain makers tend to be more valuable, but if a violin has been refinished, the value may go down. Or, if it has amazing sound but is from an unknown maker, it may still be valuable.